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1996-2000 NOAA/USGS/NASA Airborne LiDAR Assessment of Coastal Erosion (ALACE) Project for the US Coastline

This data set includes data collected from 1996-2000 and covers the states of AL,FL,LA,MS,DE,MD,VA,CT,MA,ME,NH, NJ,NY,RI,NC,SC,GA,CA OR,WA,TX OH,PA. Laser beach mapping uses a pulsed laser ranging system mounted onboard an aircraft to measure ground elevation and coastal topography. The laser emits laser beams at high frequency and is directed downward at the earth's surface through a port opening in the bottom of the aircraft's fuselage. The laser system records the time difference between emission of the laser beam and the reception of the reflected laser signal in the aircraft. The aircraft travels over the beach at approximately 60 meters per second while surveying from the low water line to the landward base of the sand dunes.

Cite this dataset when used as a source.

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    Distribution Formats
    • LAZ
    Distributor DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    Point of Contact DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    843-740-1200
    ocm.info@noaa.gov
    Documentation links not available.
    Originator
    • DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    Publisher
    • DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    Date(s)
    • publication: unknown
    Data Presentation Form: Digital image
    Dataset Progress Status Complete
    Data Update Frequency: Not planned
    Supplemental Information: This data set was collected with a LIDAR (LIght Detection And Ranging) instrument designed and developed by the Observational Sciences Branch (OSB) of NASA at the Wallops Flight Facility in Virginia. The instrument, originally designed for mapping ice sheets in Greenland, is called the Airborne Topographic Mapper or ATM. The ATM II (the latest version), operates with a Spectra Physics laser transmitter, which provides a 7 nanoseconds long, 250 microjoules pulse at a frequency-doubled wavelength of 523 nanometers in the blue-green spectral region. The laser transmitter can function at pulse rates from 2 to 10 kilohertz (kHz). The laser system with a separate cooling unit weighs approximately 45 kilograms (kg) and requires approximately 15 amperes of power at 115 volts. The transmitted laser pulse is reflected to the surface of the earth with the aid of a small folding mirror mounted on the back of a secondary mirror of a rotating scan mirror assembly mounted directly in front of the telescope. The scan mirror, which is rotated at 20 hertz, is comprised of a section of round aluminum stock, machined to a specific off-nadir angle. A scan mirror with the off-nadir angle of 15 degrees was utilized, producing an elliptical scan pattern with a swath width equal to 50 percent of the approximately 700-meter aircraft altitude. The reflected laser pulse is transmitted to a photo-multiplier assembly that consists of a lens, a narrow bandpass filter, and a single photomultiplier tube. Note: The Spatial Reference section of this document may lack fully FGDC-compliant information regarding projection parameters (i.e., Central meridian, false Northing, etc.). The State Plane or UTM Zone will be supplied, and the corresponding parameters can be found in Appendix C of: Snyder, John, 1987, Map Projections, a Working Manual (U.S. Geological Survey Professional Paper 1395): Washington, U.S. Government Printing Office.
    Purpose: This data was collected as part of an effort to map beach topography efficiently and cheaply.
    Use Limitations
    • These data depict the elevations at the time of the survey and are only accurate for that time. Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations. Any conclusions drawn from analysis of this information are not the responsibility of NOAA or any of its partners. These data are NOT to be used for navigational purposes.
    Time Period: 1996-10-09  to  2000-11-02
    Spatial Reference System: Ellipsoid in Meters
    Spatial Bounding Box Coordinates:
    N: 47.885630
    S: 25.633621
    E: -69.692954
    W: -124.621351
    Spatial Coverage Map:
    Themes
    • lidar
    • laser
    • beach
    • Bathymetry/Topography
    • digital elevation model
    • DEM
    • erosion
    Places
    • U.S. Coastline
    • Alabama
    • Delaware
    • Maryland
    • North Carolina
    • South Carolina
    • Virginia
    • Connecticut
    • Massachussetts
    • Maine
    • New Hampshire
    • New Jersey
    • New York
    • Rhode Island
    • Florida
    • Louisiana
    • Mississippi
    • Georgia
    • California
    • Oregon
    • Washington
    • Texas
    • Ohio
    • Pennsylvania
    Use Constraints No constraint information available
    Fees Fee information not available.
    Lineage Statement Lineage statement not available.
    Processor
    • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
    Processing Steps
    • The vertical values in this data set have been filtered through visual inspection to find abnormally high and abnormally low values. In addition, this data was processed using a spatial filtering program that identifies and discards outlier elevation measurements. This program reads each elevation measurement within a file and identifies "spatially close" points (i.e. those neighboring points within a fixed radius of the point). The mean and standard deviation is calculated using the elevations of these points. If the elevation difference from the mean of the point under consideration is more than 2 standard deviations and greater than a defined distance the point is discarded.
    • The NOAA National Geophysical Data Center (NGDC) received lidar data files via ftp transfer from the NOAA Coastal Services Center. The data are currently being served via NOAA CSC Digital Coast at http://www.csc.noaa.gov/digitalcoast/. The data can be used to re-populate the system. The data are archived in LAS or LAZ format. The LAS format is an industry standard for LiDAR data developed by the American Society of Photogrammetry and Remote Sensing (ASPRS); LAZ is a loseless compressed version of LAS developed by Martin Isenburg (http://www.laszip.org/). The data are exclusively in geographic coordinates (either NAD83 or ITRF94). The data are referenced vertically to the ellipsoid (either GRS80 or ITRF94), allowing for the ability to apply the most up to date geoid model when transforming to orthometric heights.

    Metadata Last Modified: 2013-05-07

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